4340 Steel Connecting Rods

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4340 Steel Connecting Rods

• Javier A. Lozano
• Material Science
• MEEN 3344

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Background

• Factory connecting rods are mass produced
• Cast from regular automotive grade Iron

• Reasons
• Faster
• Easier
• Cheaper

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Background Continued

• I-Beam design reinforces wrong face
• 4 stroke engine revolution places
• Moment load
• Compression load
• Tension load

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When Regular Rods Go Bad

• Factory Rods are usually the weak link

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New Design, New Material

• New H-Beam design places reinforcement on the
  proper face

• AISI 4340 Steel is the most common
• Other Materials also used
• Titanium
• 7075 T-6 Aluminum
• Nodular Iron
• Pearlite Iron
• 5140 Steel

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H-Beam Design

• Designed on AutoCAD for low weight, high strength
• 800 HP and 7,500 Rpm Rating (for Pontiac)
• Rods and Caps are forged separately
• Optimizes grain flow
• Enhances structural Integrity
• Higher Quality control than factory

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Specifications of AISI 4340 Steel

• Density 7.85 g/cm3
• Tensile Strength (Ultimate) 1220 MPa
• Tensile Strength (Yield) 786 MPa
• Percent Elongation at Break 13.5
• Percent Reduction of Area 37.3
• Modulus of Elasticity 205 GPa
• Poissons Ratio 0.29
• Machinability 50
• Shear Modulus 80 GPa
• All Specifications are for AISI 4340 Steel,
  normalized, 50 mm round

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References

• Callister, William D. Fundamentals of Material
  Science and Engineering an integrated approach.
  Hoboken John Wiley Sons, Inc, 2005.
• C.A.T. (2005). AISI 4340 "H" BEAM SUPER RACING
  ROD - 3D. C.A.T. Power Engine Parts. Retrieved
  February 22, 2006. from http//www.catpep.com/catp
  roducts/connectingrod/4340HBeamsuperracingrod.asp
• Eagle S P. (2006). "ESP" H-beam connecting rods.
  Eagle Specialty Products, Inc. Retrieved February
  28, 2006. from http//www.eaglerod.com/
• ASM Material Data Sheet. (2003). AISI 4340 Steel,
  normalized, 50 mm (2 in.) round. ASM Aerospace
  Specification Metals, Inc. Retrieved February 24,
  2006. from http//asm.matweb.com/search/SpecificMa
  terial.asp?bassnumM434AD
• Summit Racing Equipment. (2006). ESP-6625PP3D.
  AUTOSALES, Inc. http//store.summitracing.com/defa
  ult.asp?target/egnsearch.aspN400075
• Wikipedia. (2006). Connecting Rod Wikipedia,
  the free Encyclopedia. Wikimedia Foundation, Inc.
  Retrieved January 1, 2006. http//en.wikipedia.org
  /wiki/Connecting_rod

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Any Questions?